+require 'i18n/backend/base'
+require 'active_support/json'
+require 'active_support/ordered_hash' # active_support/json/encoding uses ActiveSupport::OrderedHash but does not require it
+
+module I18n
+ module Backend
+ # This is a basic backend for key value stores. It receives on
+ # initialization the store, which should respond to three methods:
+ #
+ # * store#[](key) - Used to get a value
+ # * store#[]=(key, value) - Used to set a value
+ # * store#keys - Used to get all keys
+ #
+ # Since these stores only supports string, all values are converted
+ # to JSON before being stored, allowing it to also store booleans,
+ # hashes and arrays. However, this store does not support Procs.
+ #
+ # As the ActiveRecord backend, Symbols are just supported when loading
+ # translations from the filesystem or through explicit store translations.
+ #
+ # Also, avoid calling I18n.available_locales since it's a somehow
+ # expensive operation in most stores.
+ #
+ # == Example
+ #
+ # To setup I18n to use TokyoCabinet in memory is quite straightforward:
+ #
+ # require 'rufus/tokyo/cabinet' # gem install rufus-tokyo
+ # I18n.backend = I18n::Backend::KeyValue.new(Rufus::Tokyo::Cabinet.new('*'))
+ #
+ # == Performance
+ #
+ # You may make this backend even faster by including the Memoize module.
+ # However, notice that you should properly clear the cache if you change
+ # values directly in the key-store.
+ #
+ # == Subtrees
+ #
+ # In most backends, you are allowed to retrieve part of a translation tree:
+ #
+ # I18n.backend.store_translations :en, :foo => { :bar => :baz }
+ # I18n.t "foo" #=> { :bar => :baz }
+ #
+ # This backend supports this feature by default, but it slows down the storage
+ # of new data considerably and makes hard to delete entries. That said, you are
+ # allowed to disable the storage of subtrees on initialization:
+ #
+ # I18n::Backend::KeyValue.new(@store, false)
+ #
+ # This is useful if you are using a KeyValue backend chained to a Simple backend.
+ class KeyValue
+ module Implementation
+ attr_accessor :store
+
+ include Base, Flatten
+
+ def initialize(store, subtrees=true)
+ @store, @subtrees = store, subtrees
+ end
+
+ def store_translations(locale, data, options = {})
+ escape = options.fetch(:escape, true)
+ flatten_translations(locale, data, escape, @subtrees).each do |key, value|
+ key = "#{locale}.#{key}"
+
+ case value
+ when Hash
+ if @subtrees && (old_value = @store[key])
+ old_value = ActiveSupport::JSON.decode(old_value)
+ value = old_value.deep_symbolize_keys.deep_merge!(value) if old_value.is_a?(Hash)
+ end
+ when Proc
+ raise "Key-value stores cannot handle procs"
+ end
+
+ @store[key] = ActiveSupport::JSON.encode([value]) unless value.is_a?(Symbol)
+ end
+ end
+
+ def available_locales
+ locales = @store.keys.map { |k| k =~ /\./; $` }
+ locales.uniq!
+ locales.compact!
+ locales.map! { |k| k.to_sym }
+ locales
+ end
+
+ protected
+
+ def lookup(locale, key, scope = [], options = {})
+ key = normalize_flat_keys(locale, key, scope, options[:separator])
+ value = @store["#{locale}.#{key}"]
+ value = ActiveSupport::JSON.decode(value)[0] if value
+ value.is_a?(Hash) ? value.deep_symbolize_keys : value
+ end
+ end
+
+ include Implementation
+ end
+ end
+end